Fox television faced an uncomfortable future when the two biggest stars on American Idol, openly discussed leaving, which experts said can send viewership plummeting.

Fox television this week faced an uncomfortable future when the two biggest stars on its No. 1-rated show American Idol openly discussed leaving, which experts said could send viewership plummeting in future seasons.

Paula Abdul, whose often quirky behavior has been a hot topic for years, told ABC News program "Nightline" that her contract ends after this season. And acid-tongued Simon Cowell, whom critics call the show's real star, gave several interviews in which he contemplated an exit when his deal ends next year.